cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A029047 Expansion of 1/((1-x)*(1-x^3)*(1-x^6)*(1-x^10)).

Original entry on oeis.org

1, 1, 1, 2, 2, 2, 4, 4, 4, 6, 7, 7, 10, 11, 11, 14, 16, 16, 20, 22, 23, 27, 30, 31, 36, 39, 41, 46, 50, 52, 59, 63, 66, 73, 78, 81, 90, 95, 99, 108, 115, 119, 130, 137, 142, 153, 162, 167, 180, 189, 196, 209, 220, 227, 242, 253, 262, 277, 290, 299, 317, 330
Offset: 0

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Author

Keywords

Comments

Number of partitions of n into the first four triangular numbers, 1, 3, 6 and 10.

Crossrefs

Cf. A008620.

Programs

  • Maple
    M:= Matrix(20, (i,j)-> if (i=j-1) or (j=1 and member(i, [1, 3, 6, 14, 17, 19])) then 1 elif j=1 and member(i, [4, 7, 9, 11, 13, 16, 20]) then -1 elif j=1 and i=10 then 2 else 0 fi): a:= n-> (M^(n))[1,1]: seq(a(n), n=0..80); # Alois P. Heinz, Jul 25 2008
  • Mathematica
    CoefficientList[Series[1/((1-x)(1-x^3)(1-x^6)(1-x^10)),{x,0,70}],x] (* Harvey P. Dale, Feb 06 2020 *)
  • PARI
    Vec(1/((1-x)*(1-x^3)*(1-x^6)*(1-x^10))+O(x^99)) \\ Charles R Greathouse IV, Sep 27 2012
    
  • PARI
    a(n)=floor((2*n^3+60*n^2+527*n+1243+9*(n+1)*(-1)^n+(120*(n\3+1)*[1,1,-2]+20*[61,41,0])[n%3+1])/2160) \\ Tani Akinari, May 07 2014

Formula

a(n) = floor((2*n^3 + 60*n^2 + 567*n + 9*n*(-1)^n + 2160)/2160 - (n/18)*[(n mod 3)=2] + (1/5)*([(n mod 6)=0] - [(n mod 6)=5])). - Hoang Xuan Thanh, Jul 06 2025